Snap acting switch having a thin leaf spring with a portion thereof bent at an obtuse angle to the remainder



April 26, 1966 J. H. STAFFORD 3,248,496

SNAP ACTING SWITCH HAVING A THIN LEAF SPRING WITH A PORTION THEREOF BENT AT AN OBTUSE ANGLE TO THE REMAINDER Filed June 7, 1960 4 Sheets-Sheet l IN VEN TOR 5 /OSLPH flfimrrako ATTORNEYS April 1966 J. H. STAFFORD 3, 8, 9

SNAP ACTING SWITCH HAVING A THIN LEAF SPRING WITH A PORTION THEREOF BENT AT AN OBTUSE ANGLE TO THE REMAINDER Filed June 7, 1960 4 Sheets-Sheet 2 IN VENTOR 5i 7 5 E1 7 Z (/0504 /4Fme0 ATTORNEYS Aprll 26, 1966 J. H. STAFFORD 3,248,496

SNAP ACTING SWITCH HAVING A THIN LEAF SPRING WITH A PORTION THEREOF BENT AT AN OBTUSE ANGLE TO THE REMAINDER Filed June '7, 1960 4 Sheets-Sheet 5 April 26, 1966 J. H. STAFFORD 3,248,496

SNAP ACTING SWITCH HAVING A THIN LEAF SPRING WITH A PORTION THEREOF BENT AT AN OBTUSE ANGLE TO THE REMAINDER Filed. June 7, 1960 4 Sheets-Sheet 4 I33 *r-F F I v n t 4 142 |4s my I I47 m M1 r INVENTOR Joseph H. Stafford ATTORNEYJ' United States Patent 3,248,496 SNAP ACTING SWITCH HAVING A THIN LEAF SPRING WITH A PORTION THEREOF BENT AT AN OBTUSE ANGLE TO THE REMAINDER .Ioseph H. Stafford, Whitehall, Ohio, assignor to Columbus Electric Manufacturing (30., Columbus, Ohio, a corporation of Ohio Filed June 7, 1960, Ser. No. 35,339 19 Claims. (Cl. 200-67) ice FIGURE 2 is an end elevation view in section of the switch taken along lines 22 of FIGURE 1;

FIGURE 3 is a top plan view of the upper fixed switch contact arm FIGURE 4 is a top plan view of the center arm 36;

. FIGURE 5 is a bottom view in partial section of the switch taken along lines 5-5 of FIGURE 1;

FIGURE 6 is a side view of a further switch construction embodying certain aspects of the present invention;

FIGURE 7 is a front elevation view of the switch of FIGURE 6;

meeting numerous high performance requirements for specialized industrial purposes.

Snap-acting switches of the general type as shown in US. Patent No. 2,558,219 for example, are extensively used in industrial equipment and home appliances for many purposes. Newly designed equipment, such as pressure and temperature sensitive controls, utilize the precisely controlled position for actuating the switch contacts as an integral part of the equipment design. This is possible largely as the result of the precise position of the actuator which causes the switch contacts to transfer.

One principal object of the present invention is to provide a snap acting switch having a novel flexible arm with a movable contact which has as an integral part thereof a spring member cooperating with the actuating member for effecting the snap acting movement. The novel snap acting switch in accordance with this invention has fewer component parts and is less expensive to manufacture while retaining the desired performance characteristics of the prior precision snap acting switches.

A further and more detailed object of this invention is to provide a snap acting switch having a novel flexible arm carrying a movable contact in the center thereof with a straight portion and an integral arcuate portion on opposite sides of the contact.

Another object of this invention is to provide a novel switch housing and contact arm arrangement.

Another principal object of this invention is to provide novel actuating members for effecting substantially straight line movement of one end of the snap acting spring element which causes actuation of the switch contacts.

A still further object is to provide in a snap acting switch of the foregoing type, an extra blade in addition to the normal actuating member which is stiffer than the actuating member and novelly arranged on the switch to enable one sized switch to be mounted in a variety of appliances and receive an actuating force displacement anywhere along the extra blade. Such an arrangement provides an infinite permutation of operating positions and combinations of displacements and operating forces.

A further object of this invention is to provide a novel U-shaped actuating member with rigid legs and center portions for controlling operation of the switch contacts. By use of stiffening ridges, it is possible to make actuating members in accordance with the present invention which provide a smaller operating differential, improved repeatability of operation and require less actuating force than has heretofore been necessary for precision switches of this general type.

These and other objects of the invention will become more fully apparent from the description and claims, and

from the appended drawings wherein:

FIGURE 1 is a side elevation view of an enclosed switch constructed in accordance with the present invention with a side cover for the housing removed;

FIGURE 8 is a front elevation view of a still further switch construction embodying certain aspects of the present invention;

FIGURE 9 is a side view of the switch of FIGURE 8;

FIGURE 10 is a front elevation view of another embodiment of the switch construction;

; IGURE 11 is a side view of the switch of FIGURE 10;

FIGURE 12 is a sectional view taken on line 1212 of FIGURE 11;

FIGURE 13 is a side view of another switch device embodying certain aspects of the present invention;

FIGURE 14 is a front elevation in section of the switch device shown in FIGURE 13 taken along lines 1414 of FIGURE 13; and

FIGURE 15 is a front elevation of the switch device shown in FIGURES 13 and 14 to clearly show the extra blade 147.

Referring now to FIGURE 1, the electrical switch contacts and actuating members are supported in a generally rectangular housing or base 10 of a suitable insulation material which is shown in the drawings with the front cover removed. Front surface 12 is a planar surface and is provided with four through apertures 14 at each of the corners for receiving suitable fastening means for mounting the switch. Recessed slightly behind front surface 12 is a further substantially flat surface 16 which on the left-hand side of the housing shown in FIGURE 1 contains a plurality of indentations or recesses. The indentations or recesses extend rearwardly to a further surface 18 parallel to rear side 19 and are sufficiently deep to receive the several switching members described in detail below.

Housing 10 contains an upper contact support portion 22 and a lower contact support portion 24, the front surfaces of which lie in a plane common with surface 12. A central projecting nose comprising bosses 26 and 28 is provided between upper and lower portions 22 and 24 to define upper and lower channels which receive upper and lower fixed contact arms 30 and 32. A similar channel is provided between bosses 26 and 28 to receive the center or movable switch arm 36.

At the bottom of each of the channels receiving contact arms 30 and 32 and the channel receiving the center switch arm 36, three projecting surfaces 38, 39 and 40 are provided. In FIGURE 5, which is a partial section taken as indicated in FIGURE 1, projection 38 is shown in detail. Projections 39 and 40 are identical with projection 38.

Inside of the housing cavity, further upper and lower channels 42 and 44 respectively, which are symmetrical about the horizontal centerline of the switch housing 10 and which have end channel extensions 43 and 45 respectively directed toward the switch arms, are provided for receiving the ends of the switch actuating member 46 which may also be characterized as a swing piece. A vertical throughbore is provided in the upper wall 48 to receive the actuating push rod 50 which is slidably mounted through the aperture in upper wall 48.

Referring now to FIGURES 1 and 3, the upper fixed a contact arm 30 is made of a suitable metal and of a sufficient size to be rigid. The usual contact point 52 is provided at the inner end and a suitable terminal aperture 54 is provided at the outer end. Inter-mediate the outer end and the inner end is an angularly bent portion 56 which fits in the channel between upper boss 26 and upper contact support portion 22. Keyway 58 in contact arm 30 engages projection 38 in surface 18 of housing 10 to assure proper positioning of upper contact arm 30 properly within the housing.

Lower contact arm 32 is formed identically with upper contact arm 30 with contact point 59, terminal aperture 60 and angularly disposed intermediate section 62. A keyway in contact arm 32 similar to keyway 58 in upper contact arm 30 engages projection 40 in surface 18 of housing 10 to assure proper positioning of lower contact 32 in the housing.

Referring now to FIGURES 1, 2 and 4, the center arm assembly comprises a single integral strip 64 of suitable resilient metal such as beryllium copper, steel or the like, having contact points 66 and 68 which are suitably secured as by riveting so as to extend on opposite sides of strip 64. At the outer end of arm 36, a strip of metal 69 having end surface 70 is bent into a U-shaped sleeve as clearly shown in FIGURE 2 to extend through the channel between bosses 26 and 28 in housing 10 and to add rigidity to the outer end of center blade 36. At the extremity of the outer end, an aperture 72 is provided to serve as a convenient terminal.

At the right side of contact points 66 and 68 as viewed in FIGURE 1, there is an abrupt deformation or bend 74 which is set in flexible arm 64 so that the arched portion 76, when unrestrained, takes the position shown in dotted lines at 78 in FIGURE 1. With the arc length of arched portion 76 about inches long, the bend is such that free position of portion 76 shown in the dotted lines 78, makes an angle of between 30 and 40 with the horizontal centerline through the switch. The free inner end 80 of arched portion 76 is bent downwardly in final assembly so that the horizontal chord distance is about inch shorter than the arc length to form the illustrated arcuate portion 76. Since arcuate portion 76 is made of a resilient material, the force at bend 74 always urges one of the contacts 66 or 68 to be in engagement with one or the other of fixed contacts 52 or 59 depending upon whether the vertical position of free end 80 of arcuate portion 76 is below or above the horizontal centerline of the switch between fixed contacts 52 and 59.

Actuating member 46 is substantially U-shaped having an upper leg 82 and a lower leg 84. At the free ends of each of legs 82 and 84, suit-able right angle bends are provided so that actuating member 46 is secured to housing in groove extensions 43 and 45. Suflicient clearance is provided so that the only contact which main actuating member 46 has with housing 10 is in the channel portion extensions 43 and 45.

On lower leg 84 of main actuator member 46 a central stiffening rib 86 extends from near the fixed end at extension 45 to the upwardly curved portion 88 which joins with a central section 90 of the actuating member. The purpose of rib 86 is to prevent leg 84 from bending or flexing during actuation of the switch at any position where the rib is provided. While stiffening rib 86 can be provided by any convenient or conventional construction, a satisfactory stiffening of leg 84 can be inexpensively obtained by simply providing a longitudinal depression as shown in FIGURE 2 which gives the effect of stiffening leg 84 insofar as the bending moment is concerned.

A similar stiffening ridge 92 is provided in upper leg 82 of switch actuating member 46 which extends from a position adjacent channel extension 43 to curved section 94 which joins with central section 90. Ridge 92 may be formed similarly to ridge 86 to provide the proper rigidity of arm 82 so that the bending or flexing takes place near its fixed end in slot 43 and at the curved section 94.

End section 90 of actuating member 46 is provided with a similar stiffening rib or ridge 96. The pointed free end of arched section 76 of center arm 64 is positioned at the bottom 98 of the depression forming the stiffening ridge 96 of end section 90. A simple mechanical frictional connection is thus provided which holds the inner section 76 of the center blade into the form of an arch and causes the free end 80 thereof to move upwardly and downwardly with movement of the central section of the switch actuating member 46. Other types of connections, such as the tongue and groove connection shown in the switch embodiments illustrated in FIGURES 6 and 7 and in FIGURES l 01 2 maybe used if desired.

The lower end of switch actuator push rod 50 is provided with a cap 104) of suitable insulating material such as nylon, which abuts against the upper surface of curved section 94 so that upon depression of actuator push rod 50, end section 90 of main actuator member 46 is forced downwardly. Cap 100 further serves as a stop to limit upward movement of upper leg 82 of the main actuator blade 46.

In operation, when actuator member 50 is pressed downwardly, legs 82 and 84 of main actuating member 46 are flexed with bending occurring in the end sections near the fixed points in slots 43 and 45 and flexing occurring in curved sections 88 and 94. Since upper legs 82 and lower legs 84 are in effect rigid links of constant length, the upper end of curved section 94 and the lower end of curved section 88 effectively pivot about respective fixed points near slots 43 and 45 in an arcuate path. Since leg 82 is substantially at a right angle with respect to a base line joining the effective pivot points near slots 43 and 45, curved section 94 has a slight component of movement inwardly toward the switch contacts when actuator rod 50 is depressed.

Lower leg 84 of the main actuator member 46 is disposed at an angle slightly less than 90 with respect to the base line described above, and hence curved section 88 has a slight component of movement away from the switch contacts in its arcuate path about a fixed point in slot 45. Center section 90 in the main switch actuator member 46 is in effect a rigid link. There is a slight component of movement toward the switch components at the upward end of section 90 and a slight componentof movement away from the switch contacts at the lower end of portion 90, but the plotted path of the end 80 of the arcuate section 76 of the center arm 64 in the switch assembly moves in almost a perfectly straight line to provide the desired straight line movement for the free end 80 rather than pivotal movement as has been customary in many prior art switches of this type.

The translational movement as compared with pivotal movement results in important advantages in precision switches. One important advantage is decreased operating differential, that is, the displacement between the positions of actuating push rod 50 causing the switch contacts to transfer between its two alternate positions.

This arrangement of parts is also advantageous because center blade arm 64 is under compression to pivot about the end of sleeve 69 thereby reducing the amount of flexing at any localized position. Where the space between switch contact points 52 and 59 is small so that the length of movement of contacts 66 and 68 on blade 64 is about inch, only a very small and almost imperceptible amount of flexing occurs at bend 74 adjacent the movable contact to be much less than the elastic limit whereby no fatigue of the metal occurs, to give the switch a long life. If perceptible flexing appears it may be desirable to reduce the cross-section of arm 64 at bend 74 as by punching out a small aperture 104 shown in FIGURE 4 to increase the length of life of the switch.

In summarizing, it will be observed that the main actuating U-shaped member 46 is anchored at both ends in channels 43 and 45 thus balancing the bending moment about the points of bending in each of legs 82 and 84.

Center section 96 has substantially only translational motion in view of the rigidity of legs 82 and 84 and very little lateral motion occurs. This construction results in improved repeatability of the trip point, that is moment of separation of contacts, because the relative motion of the main switch actuating member 46 and the movement of the center arm 64 is nearly symmetrical about the trip point.

Also, there is no lost motion on the part of movable contacts 66 and 68 on center blade arm 64 in a lateral direction because the movement of contacts 66 and 68 tends to be in a straight line rather than along an arc since the compression force on arched section 76 and substantially straight section 64 tends to counterbalance the tendency of contacts 66 and 68 to take an arcuate path about either point 76 or 80.

Another advantage of the present switch is that the operating force differential is smaller than in prior switches of this type because upper and lower legs 82 and 84 of the main actuator member 46 may be made thinner than in the case of a single main actuating member thereby resulting in a decreased spring gradient on the main actu- .ating blade member 46 whereby the return force supplied by center blade 64 and particularly through arcuate section '76 is larger for an equivalent amount of operating force. It will be observed that the cross-sections of actuating member 46 are the same size and of the same material as used in center arm 64.

The basic construction as shown is also advantageous in that the housing of the switch is substantially symmetrical so that by reversal of the main switch actuator member 46 whereby arm 82 is on the bottom andarm 84 on top, switch actuator 50 can be reversed to the lower side of housing 10 to thereby be actuated from a bottom position.

The basic switch construction may also be used as a set-type switch, that is one which remains in an operated an embodiment, legs 82 and 84 should be made flexible but without resilience, and both legs disposed symmetrically about the horizontal centerline of the switch. By adding a second actuator push rod, as on the bottom side of housing 10, the switch actuator member 46 will stay in whichever of its upper or lower positions it is moved.

Different ones of the several foregoing advantages are obtainable in various modifications of the switch described in connection with FIGURES 1 through 5. For example, in FIGURES 6 and 7, there is illustrated a second switch construction embodying the principles of certain features of the present invention. The general switch construction 18 similar to that shown in FIGURES 1-3 of Patent No. 2,558,258 and comprises a pair of bolts 110 and 112 upon which are mounted alternate metal and insulator strips held in position by nuts 114 and 116. In this embodiment, contact arms 118 and 120 are rigid members and are separated from the flexible center arm 122 carrying mov able contacts 124 and 126 by insulation spacers 128 and 130, respectively. All metal parts are insulated from bolts 116 and 112.

The actuator member 132 is illustrated as being in contact with the center flexible arm, though a further insulation spacer may be used if desired to insulate the actuator member from the flexible arm. An insulation shield 129 is provided between actuator member 132 and contact arm 118.

Actuator member 132 has a free end portion 133 joined by spaced legs 134 and 136 to ends thereof mounted in the fixed stack of insulator and conducting layers. As shown in FIGURE 7 legs 134 and 136 of actuating member 132 define two sides of a central aperture straddle and lie substantially parallel to the inner flexible arm 122 carrying contacts 124 and 126. At the end of the central aperture adjacent the movable free end of actuator member 132 there is provided a tongue 138 which is adapted to fit into a slot 140 in the arcuate spring member 142 which effects the snap action of the switch contact.

As in the embodiment shown in FIGURES 1-5, this embodiment utilizes the center arm formed of a flexible material which is also resilient, such for example as beryllium copper or steel, there being a substantially straight portion between the fixed end of flexible arm 122 and the contacts "124 and 126 and an arcuate shaped spring section 142 joined integrally with the resilient arm at bend 144. The resilience of arcuate section 14-2 serves to place flexible arm 122 under compression so that the position of the switch contacts is determined by the position of the free end 133 of actuating member 132, which free end effectively pivots or moves in an arcuate path about the fixed end of actuating member 132.

The free end 146 of arcuate member 142 is provided with a slot which is adapted to fit over the end of tongue 138 on the free end 133 of actuating member 162. The resilience of the arcuately curved section 142 provides the spring force which effects the transfer of the switch contacts in accordance with the position of the free end 133 of the actuating member 132.

Where actuating member 132 is made of material flexible and not resilient, the switch becomes a two-position switch which is transferred to the desired position by a force acting on the. free end of actuating member. Where the actuating member is also resilient, the switch has a normally closed set of contacts which are opened only during the application of a force on the free end of actuating member as indicated in FIGURE 6.

The action of flexible center arm 122 carrying movable contacts 124 and 126 is the same in this embodiment as in the embodiment illustrated in FIGURES 1- 5. The integral construction of the center flexible arm 122 having the resilient arcuate section 142 at one free end thereof simplifies the switch assembly and reduces the cost of construction while at the same time provides the precisely controlled switch action of the more expensive prior art switches.

In FIGURES 8 and 9, a further embodiment of the present invention is illustrated. The switch is mounted on a pair of bolts 1 50 and 152, and comprises a series of electrically conducting members, insulated from bolts 150 and 152, and insulated from one another by spacers 154 of insulation material. Metal plates 156 and 158 are provided to serve as bearing surfaces adjacent the heads of bolts 150 and 152 and nuts 160 and 16-2.

Fixed contact 164 is carried on a rigid arm 166 of conducting material to which an external connection may be made by connecting onto tab 168. Parallel to arm 166 is a second rigid arm 170 of a suitable material such as steel, having free end 172 mechanically connected to arm 166 at the location of contact 164 by a spacer 174 of insulation material. Rigid arm 17d and spacer 174 serve to enhance the rigidity of rigid arm 166 and are not essential where arm 166 is so constructed as to be completely rigid.

Movable contact 176 is carried by an arm 178 of flexible, resilient material which is substantially identical with the center blade arm 64 in the switch embodiments described above. An external connection tab 179 is provided on movable arm 17%. tRigid arm 180 is similar to arm 170 described above and carries insulation spacer 182. Spacer 182, which is secured to arm 180 serves as a mechanical stop for movable arm 178 adjacent contact 176.

Switch actuating member 184 is generally U-shaped having a left leg 1'86 and a right leg 188 as viewed in FIGURE 9 bent as illustrated to be movable to the left when contacts 164 and 176 are to open and to the right when the cont-acts are to close. The open ends of legs 186 and 188 are secured to the several insulation layers and underneath the outer plates held together by bolts 150 and 15 2 and are joined at their other ends by a substantially straight section 190 through curved flexible sections 192 and 194. Each of legs 186 and 188 and straight section 190 are made rigid as by providing stiffening ridges 196 so that the bending in legs 1% and 188 occurs only at the positions adjacent the fixed insulation spacers 154 and flexing occurs in curved sections 192 and 194.

The free end 198 of the movable arm 178 fits into a depression 200 in straight section 190 of the actuating member 134 to be movable therewith. Since legs 186 and 18 8 are symmetrical about a center line through the actuator member, a force applied at the position and in the direct-ion of arrow 202 will cause straight section 190 to have translational movement. By locating depression 200 at a position just slightly to the left as viewed in FIGURE 9 of the straight portion of movable arm 178 extended, a very sensitive switch requiring only a small displacement of the actuating member may be obtained thereby providing a small operating dilferential, and at the same time, the switch will not be inadvertently actuated by vibration or other similar causes.

A further advantage over the switch embodiments de-- scribed above resides in the use of only one fixed contact whereby both the size of the contacts and the spacing therebetween can be increased to increase the current capacity and voltage rating of the switch. Because of the unique integral construction of the flexible arm and arched section 204 the displacement of the movable contact is limited to a relatively small distance. For many low voltage, low current switching applications, the advantageous cost consideration and other improved characteristics of the embodiments shown in FIGURES 1 through 5 and 6 and 7 outweigh this inherent limitation, while for higher power requirements the switch embodiment shown in FIGURES 8 and 9 'has been found to be preferred.

The embodiment illustrated in FIGURES 10 through 12 is generally similar to the embodiment just described in connection with FIGURES 8 and 9, and only the differences will be discussed in detail below. The center flexible arm 21'0 carrying the movable contact 212 has at its free end a tongue 214 which is moved by the actuating member assembly 216.

Actuating member assembly 216 comprises a pair of flexible resilient arms 218 and 220 which are secured at one end underneath outer metal plates 2'22 and 224 and at the other ends have slots in portions 226 and 228 which are bent at right angles as clearly shown in FIG- URE 11. A U-shaped member 230 having legs 232 and 234 extending through the slots with shoulders abutting against end portions 226 and 228 and a main body portion 236 is carried by arms 2'18 and 220. A stiffening ridge 238 ispreferably provided along body portion 236. One or more stiffening ridges 240 may also be provided along arms 218 and 220 if desired, though in this embodiment the stiffening ridges are not essential because of the extremely low resistance to changes in angular position between arms 218 and 220 and member 230 due to the tongue and groove connections.

A suitable slot 242 in body section 236 is provided to receive tongue 214 on the end of movable contact arm 210. With a force applied at the position and along the direction of arrow 244, U-shaped member 230 is given substantially straight line movement to cause movable arm 210 to snap to the left as viewed in FIG- URE 11 and to close contacts 212 and 246. As with the construction shown in FIGURES 8 and 9, this embodiment also permits the use of large switch contacts with sufiicient spacing between the contacts for high voltage operation.

With reference now to FIGURES 13, 14 and 15, the switching device here illustrated in identical to the embodiment shown and described in connection with 8 FIGURES 6 and 7 excepting for a further blade member 147 and spacer 149.

Blade member 147 is a flat member made of a resilient and flexible material and secured to the support provided by the spacers and contact arms in conjunction with fasteners .110 and 112. Bladd member 1 47 is stiffer than actuating member 132 as by making member 147 thicker than member 132, the relative thicknesses being illustrated in FIGURE 13. Actuating member 132 is, in turn, thicker than resilient arm 122.

Spacer 149 may be cy-lindrically shaped and secured to actuating arm 132 as by screw 148. The opposite end of spacer 149 is preferably spherically shaped so that it is free to slide along the surface of extra blade member 147 when members 147 and 132 are displaced to the left as viewed in FIGURE 13 to cause actuation of the switch and transfer of the switch contacts. Spacer 149 is preferably made of an insulating material such as nylon.

In this embodimtnt, actuating member 132 is spring biased toward extra blade member 147 to thereby continuously urge surface 145 of spacer 149 against blade member 147. A displacement force directed to the left as viewed in FIGURE 13 may be applied anywhere along the exposed outer surface of extra blade member 147 to cause actuation of the switch. The magnitude of displacement when the force is applied at the upper free end of blade 147 will necessarily be greater than that required if the force is applied nearer the fixed end, and conversely a greater force is required when applied near the fixed end than when applied at the upper free end. Extra blade member 147 is preferably sufficiently rigid so that a force of suflicient magnitude applied anywhere along member 147 at a distance of A inch or greater from the fixed end in the support will be capable of actuating the switch.

In practice, the extra blade member 147 gives an infinite permutation of operating positions to provide an infinite number of combinations of movement (displacement) and operating pressures or forces. A single sized switch of FIGURES 13-15 thus may be used in a large number of different arrangements having a variety of displacement movements and operating pressures or forces. Also, the extra blade of the present invention may be advantageously used with other snap-acting switch devices, such for example as those shown in US. Patent No. 2,558,258.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description,

and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a snap-acting switch of the type having a base, a stationary contact, a movable contact, a generally elongated snap means supported at one end by said base and carrying said movable contact, and an actuating member connected to the other end of said snap means for moving said other end substantially transverse-1y to the longitudinal axis of said snap means to effect a snap-action engagement and disengagement of said contacts; the improvement wherein said snap means solely comprises an elongated member in the form of a single piece of resilient material including a first substantially straight section and a second section joined to said first section by a sharp bend and said second section being resiliently maintained in an arcuate configuration by longitudinal compression imposed on said resilient member between said actuating member and said base, transverse move- 9 ment of said actuating member thereby resulting in a snap action within said integral strip to selectively move said contacts into and out of engagement.

2. A switch as defined in claim 1, said actuating member being effectively pivotally connected to said base.

3. A switch as defined in claim 1, said first substantially straight section being supported by said base and said second arcuately configured section being connected to said actuating member.

4. A switch as defined in cl-aim.3, said first section being fixed to said base in a cantilevered connection at said one end of said snap means.

5. A switch as defined in claim 1, said first substantially straight section carrying said movable contact adjacent said sharp bend in said elongated resilient member.

6. A switch as defined in claim 1, said movable contact being carried "by said snap means along a substantially linear path to and from engagement with said stationary contact and said actuating member being mounted to move said other end of said snap means along a path parallel to the path of said movable contact.

7. A switch as defined in claim 1, said actuating member being effectively .a U-shaped linkage, the base of said U-shaped linkage engaging said other end of said snap means and the outer ends of the legs of said U-shaped linkage being effectively pivotally connected to said base.

8. A combination as defined in claim 7, said actuating member comprising separate members serving as said legs and assaid base, said base containing a slot for receiving the other end of said snap means.

9. A switch as defined in claim 1, said actuating member being a resilient lea-f cantilevered in said base adjacent said one end of said snap means.

It). A switch as defined in claim 1; said base including a support and a pair of substantially rigid arms securely fixed to said support and extending therefrom on opposite sides of said snap means in spaced relation thereto, said stationary contact being mounted on the facing surface of one of said arms, said actuating member being a resilient blade of greater length than said snap means and having one end fixed to said support between the fixed ends of said rigid arms, said blade having an elongated aperture therein for said snap means with one end wall of said aperture engaging said other end of said snap means, said switch including a further blade member secured at one end to said support on the outer side of one of said rigid arms, the stiffness of said further blade member being greater than the stiffness of said actuating member and the actuating member being normally biased toward said further blade member, and a block of insulation material separating said actuating member and said further blade member whereby said switch may be actuated by a displacement force acting at any position along said further blade member.

11. The switch as defined in claim 10 wherein said block of insulating material is secured at one end to one of said members and rounded at the other end to slidably bear against said other member.

12. The switch as defined in claim 10 wherein said block of insulating material is secured at one end to said actuating member and rounded at the other end to slidably bear against said further blade member.

13. The switch as defined in claim 1, said actuating member comprising a flat strip of resilient material mounted parallel with said snap means and having an elongated central aperture and a fixed end adjacent to said one end of said snap means, said straight and arcuate sections of said snap means freely fitting into the aperture of said actuating member, said switch further including a blade member of resilient material mounted with one end fixed adjacent the fixed end of said actuating member, said blade member having a free end portion extending adjacent a portion of the actuating member extending beyond the central aperture and a body of insulating material mounted between said blade member and lo said actuating member at the free end portion of said blade member whereby application of a displacement force to said blade member effects a displacement of said actuating member to thereby cause actuation of said switch.

14. The switch as defined in claim 13 wherein the thickness of the actuating member is greater than the thickness of said snap means and the thickness of said blade member is greater than the thickness of said actuating member, and the actuating member is normally biased in a direction toward said blade member.

15. In combination, a switch housing of insulating material having in one side edge thereof a plurality of through openings, an elongated rigid metal strip carrying a stationary contact and extending through one of said openings, means on said strip and housing for accurately positioning said stationary contact in said housing, a flexible arm, means surrounding a portion of said flexible arm extending through and secured at one end to said housing at another of said openings, a contact carried by said arm which is movable into and from engagement with the stationary contact, means on said housing for accurately positioning said flexible arm in said housing, a U-shaped actuating member having leg members each containing a stiffening ridge anchored at the open ends thereof to said housing at positions adjacent said through openings, 2. section joining the legs of said actuating member at their other ends serving as a free end portion with the legs extending across said housing on opposite sides of said metal strip and said flexible arm to position said free end portion of said actuating member at the side of the housing opposite said one side edge, a spring member having one end connected to the flexible arm at the movable contact and the other end connected to the free end portion of said U-shaped actuating member, and push-rod means extending through a wall of said housing to contact a leg of said U-shaped actuating member whereby the free end portion of said actuating member at the position connected to said flexible arm has substantially straight line movement for controlling movement of the contact on said flexible arm.

16. In combination, a switch housing of insulating material having in one side edge thereof a plurality of through openings, first and second elongated rigid metal strips carrying stationary contacts and extending through separate ones of said openings, means on said strips and housing for accurately positioning said stationary contacts in said housing, a flexible arm extending through another of said openings and having a free end portion positioned between said stationary contacts, means surrounding said flexible arm secured to said last mentioned opening, a pair of contacts carried by said arm which are movable into alternate engagement with the stationary contacts, means on said housing for accurately positioning said flexible arm in said housing, a U-shaped actuating member having leg members each containing a stiffening ridge anchored at the open ends thereof to said housing at positions adjacent said through openings, a section joining the legs of said actuating member at their other ends serving as a free end portion with the legs extending across said housing on opposite sides of said metal strips to position said free end portion of said actuating member at the side of the housing opposite said one side edge, an arched portion of resilient material having one end connected to the flexible arm at the movable contact and the other end connected to the free end portion of said U-shaped actuating member, and push-rod means extending through a wall of said housing to contact a leg of said U-shaped actuating member whereby the free end portion of said actuating member has substantially straight line movement for controlling movement of the contact on said flexible arm.

17. In a snap acting switch device of the type com.- prising a stationary contact, a flexible arm to be actuated having a fixed end and a free end portion, and a contact carried by said arm which is movable into and from engagement with the stationary contact, said flexible arm being formed from an integral strip of resilient material and containing a substantially straight section between said fixed end and the contact on said arm and an arcuate section between the free end portion and the contact on said arm, said arcuate portion being joined to said substantially straight section by a sharp bend, and an actuating member contacting the free end portion of said arm to control opening and closing of said switch, said actuating member portion being mounted to move in substantially a straight line in a direction parallel to the direction of movement of the switch contacts, said actuating member comprising a pair of arms fixed at one end on opposite sides of and adjacent the fixed end of said flexible arm along a line parallel to said direction of movement of the switch contacts, and a rigid section joined to the ends of said arms remote from said fixed ends, and the free end portion of said flexible arm being connected to said rigid section.

18. In a snap acting switch device of the type comprising a stationary contact, a flexible arm to be actuated having a fixed end and a free end portion, and a contact carried by said arm which is movable into and from engagement with the stationary contact, said flexible arm being formed from an integral strip of resilient material and containing a substantially straight section between said fixed end and the contact on said arm and an arcuate section between the free end portion and the contact on said arm, said arcuate portion being joined to said substantially straight section by a sharp bend, and an actuating member contacting the free end portion of said arm to control opening and closing of said switch, said actuating member being mounted to move in substantially a straight line in a direction parallel to the direction of movement of the switch contacts, said actuating member comprising a pair of arms of flexible material fixed at one end on opposite sides of and adjacent the fixed end of said flexible arm along a line parallel to said direction of movement of said switch contacts, said arms being formed to be generally rigid and bendable only at locations adjacent said fixed ends, and a rigid section joined to the ends of said arms remote from said fixed ends by means permitting a change in angular relationship between said arms and said rigid section, and the free end portion of said arm being connected to said rigid section.

19. A snap-acting switch comprising, a base composed of insulating material, an actuator member connected to said base and having a portion movable in an arcuate path relative to said base, a snap member consisting of a thin leaf spring, a portion thereof being bent at an obtuse angle to the remainder of the spring, and being in a compressed bow shape and always remaining bowed in the same direction, one end of said compressed bow shaped portion being engaged by said actuator member portion and the other end of said bow shaped portion being fixed to the base, spaced stationary contacts, and movable contacts attached to the straight and unbowed portion of the spring and adapted for contact with one or the other of the spaced contacts.

References Cited by the Examiner UNITED STATES PATENTS 2,002,467 5/ 1935 Blodgett 20067 2,414,315 1/1947 McCullough 20067 2,414,778 1 1947 Tratsch 20067 2,500,476 3/ 1950 Von Stoeser 200-67 2,558,219 6/1951 Kohl 20067 2,581,705 1/1952 Riche 20067 2,603,727 7/1952 Auer 20067 FOREIGN PATENTS 965,364 2/1950 France.

BERNARD A. GILHEANY, Primary Examiner.

MAX L. LEVY, Examiner. 

19. A SNAP-ACTING SWITCH COMPRISING, A BASE COMPOSED OF INSULATING MATERIAL, AN ACTUATOR MEMBER CONNECTED TO SAID BASE AND HAVING A PORTION MOVABLE IN AN ARCUATE PATH RELATIVE TO SAID BASE, A SNAP MEMBER CONSISTING OF A THIN LEAF SPRING, A PORTION THEREOF BEING BENT AT AN OBTUSE ANGLE TO THE REMAINDER OF THE SPRING, AND BEING IN A COMPRESSED BOW SHAPE AND ALWAYS REMAINING BOWED IN THE SAME DIRECTION, ONE END OF SAID COMPRESSED BOW SHAPED PORTION BEING ENGAGED BY SAID ACTUATOR MEMBER PORTION AND THE OTHER END OF SAID BOW SHAPED PORTION BEING FIXED TO THE BASE, SPACED STATIONARY CONTACTS, AND 